1. Field of the Invention
The present invention relates to an aluminum-stabilized superconducting wire excellent in mechanical strength, thermal stability, and electrical stability and suitable as a conductor of a magnet.
2. Description of the Related Art
Conventionally, a superconducting wire obtained by burying a superconducting filament made of, e.g., Nb-Ti in a copper matrix is used as a conductor of a superconducting magnet or the like.
This superconducting wire is fabricated, e.g., in the following manner. An Nb-Ti alloy rod is inserted in a copper pipe or copper alloy pipe to form a composite billet. The composite billet is hot-extruded to be integrated. The integrated composite billet is then subjected to rolling and drawing, e.g., wire drawing. A multi-core superconducting wire is obtained by filling a multiple of resultant superconducting wires in a copper pipe to form a composite billet, and subjecting the composite billet to the processing as described above. When a necessary number of superconducting wires or multi-core superconducting wires thus obtained are intertwined, a stranded superconducting wire can be fabricated.
An aluminum-stabilized superconducting wire is obtained by covering the superconducting wire or stranded superconducting wire described above with high-purity aluminum as a stabilizing member having a residual resistance ratio (a ratio of an electric resistance at 300K to an electric resistance at 100K) much higher than that of copper. The aluminum-stabilized superconducting wire is excellent in thermal stability and electrical stability when compared to a conventional copper-stabilized superconducting wire to which only copper is covered as the stabilizing member. In addition, since the specific gravity of aluminum is 1/3 that of copper, when the superconducting wire is used in the magnet, the weight and size of the magnet can be reduced. Since the aluminum has a smaller mass than that of copper and thus has an excellent elementary particle permeability, an application of the aluminum-stabilized superconducting wire to a magnet for elementary particle detector has been studied in the field of high energy physics.
However, since high-purity aluminum of the aluminum-stabilized superconducting wire as the stabilizing member has a low mechanical strength, when the aluminum-stabilized superconducting wire is used as a conductor of a large magnet, it can be deformed by the electromagnetic force.